It was out of context.
Wait.
It was sarcasm in context.
Wait.
He likes to talk through new information out loud and he was still digesting that information.
I think Dr Birx who said the last thing is insightful. I think that was what was going on. He was trying to process new information and we were seeing him do so in real time. Unfortunately, Trump already lied by saying it was sarcasm, so Birx's comments came too late to save him.
Also, a person who absorbs information so poorly, and extrapolates such dangerous nonsense from it, is not someone who should be president.